JP2009195025A - Surface permanent magnet type rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface permanent magnet type rotating electric machine for preventing interference between a protection member for preventing scattering of magnets and a stator when a rotor rotates at high speed without being installed with a redundant air gap between the protection member and the stator when the rotor rotates at low speed. <P>SOLUTION: The rotor 12 is arranged on a rotor core 15 and the outer circumferential surface of the rotor core 15. The rotor includes the protection member 17 for preventing the scattering of magnets mounted so as to cover permanent magnets 16 in each of which the outer circumferential portion of a first edge is located radially outside the outer circumferential portion of a second edge relative to the rotor core 15. The stator 18 is disposed outside the rotor 12. The inner diameter on the first edge side of the permanent magnet 16 is formed larger than the inner diameter on the second edge side of the permanent magnet. The rotor 12 is moved along the axial direction by drive means 21. When the rotor 12 and the stator 18 are relatively displaced, a controller 26 controls the drive means 21 so that a distance between the outer circumferential surface of the permanent magnet 16 and the inner circumferential surface of the stator 18 relative to an increase in a rotational speed increases as the rotational speed of the rotor 12 increases. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface magnet type rotary electric machine, and more specifically, a permanent magnet is provided on the surface of a rotor, and the surface of the permanent magnet and the rotor is covered with a protective member for preventing scattering of the permanent magnet. The present invention relates to a surface magnet type rotating electric machine.

  As a permanent magnet type rotating electrical machine, there is a surface magnet type rotating electrical machine in which a permanent magnet is attached to the outer peripheral surface of a rotor iron core (rotor core). The surface magnet type rotating electrical machine has a structure in which the magnet is attached to the surface of the rotor core, so that the suction force between the magnet and the iron core during high-speed rotation and the strength of the adhesive filled between the magnet and the iron core are centrifugal. Since the magnet cannot withstand the pulling force due to force, the magnet may be scattered, and measures to prevent the magnet from scattering are necessary.

  As a measure for preventing the scattering of the magnet, a protective member generally formed of a non-magnetic material is provided on the outer peripheral surface of the permanent magnet, or a carbon fiber or the like is wound to prevent the scattering of the magnet. However, when the magnet is peeled off from the rotor core, the protective member receives the centrifugal force of the magnet in addition to the centrifugal force acting on itself, and extends in the radial direction. It is necessary to secure a wide length or to limit the rotation speed so as not to interfere with the stator.

  Conventionally, in order to improve the centrifugal force strength, bending strength, torsional strength, bending rigidity, and torsional rigidity of a rotor, a single fiber is wound up in layers in a predetermined direction on a magnet surface and combined with a matrix resin. A configuration has been proposed (see, for example, Patent Document 1). As shown in FIG. 6, the single fiber is wound around the surface of the magnet 60 by a hoop winding with an angle α1 formed with the axis L of 90 degrees and a helical winding with an angle α2 formed with the axis L of 15 degrees. Flexural rigidity is imparted by helical winding, and compressive stress is imparted by hoop winding.

In addition, as a vertical generator that can prevent the voltage from rising too much due to an increase in rotational speed, the axial position of the rotor relative to the stator is moved to change the magnetic flux density in the gap between the stator and the rotor, thereby rotating the rotor. There has been proposed one in which the voltage is not increased too much when the speed is increased (see, for example, Patent Document 2). In Patent Document 2, as shown in FIG. 7, in a rotating field AC generator, a rotor 62 is supported so as to be slidable in the axial direction with respect to a vertical shaft 61, and is rotated together with the vertical shaft 61 by a key 63. The The rotor 62 is configured to be movable in the axial direction. The rotor 62 has an outer periphery that is tapered so that the outer diameter of the upper end surface is larger than that of the lower end surface, and the gap 65 is narrower on the upper side and wider on the lower side. A support member 66 is fixed to the vertical shaft 61 above the rotor 62, and the rotor 62 is connected to the support member 66 through a pair of links 67. A centrifugal weight 68 is provided in the middle of the link 67. When the vertical shaft 61 rotates, the centrifugal weight 68 tends to expand in the radial direction. Then, the rotor 62 moves upward via the link 67 by the centrifugal force applied to the centrifugal weight 68. As a result, the gap 65 is uniformly wider during high-speed rotation than during low-speed rotation, and an excessive voltage rise can be prevented.
JP-A-9-19093 Japanese Utility Model Publication No. 54-175511

  By winding the fibers of the protective member by hoop winding and helical winding as in Patent Document 1, it is possible to improve the tensile strength in the radial direction and the axial torsional rigidity. However, since the protective member stretches during high-speed rotation, the design of the air gap length still takes into account the prevention of magnet scattering during high-speed rotation, that is, considering the elongation of the magnet protective member, and the redundant air gap length during low-speed rotation. . Ensuring a wide air gap length is equivalent to increasing the magnetic resistance in the air gap and also causes a problem of torque reduction.

  Further, in Patent Document 2, in the generator, the rotor 62 is automatically moved in the axial direction by the centrifugal force acting on the centrifugal weight 68 so that the generated voltage does not increase excessively when the rotor 62 rotates at high speed. ing. However, in Patent Document 2, there is a protection member provided to prevent scattering of the magnet in the surface magnet type rotating electric machine, and interference with the stator (stator) when the protection member extends in the radial direction as the rotor rotates at high speed. There is no mention of restraining it.

  The present invention has been made in view of the above-described problems, and its object is to provide high-speed rotation without providing a redundant air gap between the protective member and the stator during low-speed rotation of the rotor (rotor). It is an object of the present invention to provide a surface magnet type rotating electrical machine that can prevent interference between a protective member for preventing scattering of a magnet and a stator (stator).

  In order to achieve the above object, the invention according to claim 1 is arranged on the outer surface of the rotor core and the rotor core, and the outer peripheral portion of the first end portion has a diameter related to the rotor core rather than the outer peripheral portion of the second end portion. A rotor having a protective member for preventing scattering of magnets provided so as to cover the permanent magnet located on the outer side in the direction, and an inner diameter on the first end portion side of the permanent magnet, which is disposed outside the rotor. And a stator formed larger than the inner diameter on the second end side. Further, driving means for driving at least one of the rotor and the stator so that the rotor moves relative to the stator along the axial direction of the rotor, and the rotor and the stator are driven by the driving means. When the relative movement is performed, the increase in the distance between the outer peripheral surface of the permanent magnet and the inner peripheral surface of the stator with respect to the increase in the number of rotations increases as the rotation speed of the rotor increases in at least a part of the rotation speed range. Control means for controlling the drive means so as to increase.

In the present invention, the permanent magnet disposed on the outer peripheral surface of the rotor core is formed so that the outer peripheral portion of the first end portion is located on the radially outer side of the rotor core with respect to the outer peripheral portion of the second end portion. By moving relative to the stator along the axial direction of the rotor, the gap between the protective member and the stator is changed. When the rotor is moved relative to the stator in the axial direction, the distance between the outer peripheral surface of the rotor core and the inner peripheral surface of the stator increases as the rotational speed of the rotor increases in at least a part of the moving range. To be moved. Therefore, without providing a redundant air gap between the protective member and the stator when the rotor (rotor) rotates at a low speed, the protection member for preventing scattering of the magnet at the high speed rotation and the stator (stator) Interference can be prevented.

  According to a second aspect of the present invention, in the first aspect of the invention, the permanent magnet is formed in a shape in which a line of intersection between a plane including the central axis of the rotor and the outer peripheral surface of the permanent magnet is a straight line. ing. Therefore, in this invention, when the protective member is configured by winding fibers, it becomes easier to wind the fibers than in the case where the intersecting line has a curved shape that protrudes inward.

  According to a third aspect of the present invention, in the first aspect of the present invention, the permanent magnet has a curved line with an inward convex line between a plane including the central axis of the rotor and the outer peripheral surface of the permanent magnet. It is formed into a shape. Therefore, in the present invention, the size of the gap provided so that the protective member does not interfere with the stator is reduced as compared with the case where the line of intersection between the plane including the central axis and the outer peripheral surface is a straight line. Can do.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the control means is configured such that when the rotor and the stator move relative to each other, a rotational speed of the rotor is increased. The drive means is controlled so that the increase in the distance between the outer peripheral surface of the permanent magnet and the inner peripheral surface of the stator increases as the rotational speed increases. Even in this invention, it is possible to prevent interference between the protective member for preventing scattering of the magnet and the stator during high-speed rotation without providing a redundant air gap between the protective member and the stator during low-speed rotation of the rotor. it can.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, when the rotor and the stator move relative to each other, the control means moves the relative movement amount of the rotor. Controls the driving means so that is proportional to the square of the rotational speed of the rotor. The centrifugal force received by the protective member increases in proportion to the square of the rotational speed of the rotor. In this invention, since the relative movement amount of the rotor is moved in proportion to the square of the rotational speed of the rotor, the size of the gap provided so that the protective member does not interfere with the stator is set so that the rotor and the stator are On the premise that the distance is optimal, the relative movement amount of the rotor can be made smaller than in the case where the relative movement amount is directly proportional to the rotational speed of the rotor.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the surface magnet type rotary electric machine is an electric motor, and the driving means relatively moves the rotor in the axial direction. The preset rotation speed is a rotation speed at which a field weakening is required when the rotor is not moved.

  In general, when a surface magnet type motor is operated, power is supplied by an inverter, but maximum torque control is performed until the rotational speed reaches a predetermined speed, and control is performed so that the torque is maximized at the maximum current of the inverter. Then, field weakening control is performed in which a current that weakens the magnetic flux generated from the rotor is supplied so that the induced voltage does not become higher than the inverter input voltage in the range where the rotational speed exceeds the predetermined rotational speed. In this invention, when the rotational speed at which the field weakening is performed is exceeded, the rotor is relatively moved in the axial direction, so that the gap between the rotor core and the stator becomes large, and the induced voltage becomes low at the same rotational speed. Therefore, even if the current for field weakening is reduced during high-speed rotation of the rotor, the induced voltage can be prevented from becoming excessive, and the electric motor can be operated with high efficiency.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the driving means moves the rotor in the axial direction to move the rotor relative to the stator. Move relative. In order to move the rotor relative to the stator in the axial direction, the stator is fixed and the rotor is moved, and the rotor is only rotatable and cannot be moved in the axial direction, and the stator is moved in the axial direction. There is a method of moving both the rotor and the stator in the axial direction. In this invention, since the drive means moves the rotor in the axial direction, it is easy to suppress the increase in size of the rotating electrical machine as compared with the configuration in which the stator is moved.

  According to the present invention, the redundant air gap is not provided when the rotor (rotor) rotates at a low speed, and interference between the protective member for preventing scattering of the magnet and the stator (stator) during high-speed rotation is prevented. be able to.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a surface magnet type rotary electric motor will be described with reference to FIGS.

  As shown in FIG. 1A, an electric motor 10 as a surface magnet type rotating electric machine has a housing 11 including a bottomed cylindrical main body portion 11a and a lid portion 11b covering the opening, and a rotor 12 The rotation shaft 13 is supported rotatably with respect to the housing 11 via a bearing 14 fixed to the center of the main body 11a and the center of the lid 11b. In this embodiment, the bottom side of the main body portion 11a is described as the lower side of the electric motor 10, and the lid portion 11b side is described as the upper side of the electric motor 10.

  The rotor core 15 is formed such that the outer diameter of the first end (in this embodiment, the upper end) is larger than the outer diameter of the second end. The rotor core 15 is formed by laminating steel plates. In this embodiment, the rotor core 15 is formed in a truncated cone shape, that is, in a shape in which the intersecting line between the plane including the central axis and the outer peripheral surface is a straight line, and can rotate integrally with the rotary shaft 13 by spline fitting (not shown). It is slidable in the direction.

  As shown in FIG. 1B, the outer peripheral surface of the rotor core 15 has a plurality of arc-shaped permanent magnets 16 (six in this embodiment) whose cross-sectional shape shares the center of rotation with the rotor 12 in the circumferential direction. They are arranged at regular intervals. As the permanent magnet 16, a rare earth magnet having a strong magnetic force is used. That is, the permanent magnet 16 is disposed on the outer peripheral surface of the rotor core 15, and the outer peripheral portion of the first end portion is located radially outside the outer peripheral portion of the second end portion with respect to the rotor core 15. Further, the permanent magnet 16 is formed in a shape in which a line of intersection between a plane including the central axis of the rotor 12 and the outer peripheral surface of the permanent magnet 16 is a straight line.

  Each permanent magnet 16 is adhered to the rotor core 15 with an adhesive and is covered with a protective member 17 for preventing magnet scattering. In this embodiment, the protection member 17 is made of a fiber reinforced resin having a plurality of carbon fiber layers wound by hoop winding and helical winding as reinforcing fibers. In FIG. 1A, the protection member 17 is shown in a state separated from the permanent magnet 16 in order to clearly represent the protection member 17, but actually, the protection member 17 is in close contact with the surface of the permanent magnet 16. The protective member 17 is formed, for example, by winding a fiber impregnated with an uncured thermosetting resin (for example, epoxy resin) around the outer periphery of the permanent magnet 16 and then heat-curing it.

  A stator (stator) 18 is fixed to the outside of the rotor 12 inside the main body 11a. The stator 18 has an axial length that is the same as the axial length of the rotor core 15. The stator 18 is formed such that the inner diameter on the side corresponding to the first end of the rotor core 15, that is, the inner diameter on the upper end side, is larger than the inner diameter on the side corresponding to the second end of the rotor core 15. The stator 18 has a plurality of teeth 19 provided therein at equal intervals, and the inner diameter of the stator 18 means the distance from the center of the stator 18 to the tip surface of the teeth 19. That is, the stator 18 is disposed outside the rotor 12, and the inner diameter of the permanent magnet 16 on the first end side is larger than the inner diameter of the permanent magnet 16 on the second end side. Multiple teeth 19 are provided, and a coil (winding) 20 is wound around the teeth 19. The winding method of the coil 20 may be distributed winding or concentrated winding. In this embodiment, the angle θr formed by the intersection line between the plane including the central axis of the rotor core 15 and the outer peripheral surface and the axial direction, and the angle formed by the line formed by the plane including the central axis of the stator 18 and the inner peripheral surface. θs is configured to be the same.

  Drive means 21 is provided at the bottom of the main body 11a to drive the rotor 12 relative to the stator 18 along the axial direction of the rotor 12. A linear actuator is used as the driving means 21. A thrust bearing 22 is supported on the rotary shaft 13 at a position facing the second end of the rotor core 15 so as to be movable along the rotary shaft 13. The driving means 21 includes a moving portion 21 a via a bracket 23. The thrust bearing 22 can be pushed up. The drive means 21 is arranged so that the lower end of the rotor core 15 is at the same height as the lower end of the stator 18 excluding the coil end in a state where the moving portion 21a is arranged at the original position. The rotor core 15 has a reference position in which the lower end has the same height as the lower end of the stator 18 excluding the coil end. A thrust bearing 24 is supported on the rotary shaft 13 so as to be movable along the rotary shaft 13 in contact with the first end (upper end) of the rotor core 15. The upper surface of the thrust bearing 24 and the lid portion 11b. A coil spring 25 that urges the thrust bearing 24 downward is provided between the lower surface of the thrust bearing 24 and the lower surface.

  The drive means 21 is controlled by a control device 26 as a control means. The control device 26 includes a microcomputer (not shown) and controls the driving means 21 based on a program memory stored in the memory of the microcomputer. The control device 26 calculates the rotational speed of the rotor 12 based on a detection signal from a sensor (not shown) that detects the rotational speed of the rotary shaft 13. The control device 26 moves the rotor 12 in the axial direction in a state where the rotational speed of the rotor 12 exceeds a preset rotational speed, and as the rotational speed of the rotor 12 increases, the outer peripheral surface of the rotor core 15 and the stator 18 are increased. The driving means 21 is controlled so that the relationship between the rotational speed and the amount of movement set in advance is set so that the distance from the inner peripheral surface increases.

  When the rotor 12 cannot be moved, the control device 26 prevents the induced voltage caused by the rotation of the rotor 12 from becoming excessive, so that the drive means until the rotational speed ωs at which the field weakening control is started is reached. If the rotational speed of the rotor 12 exceeds the rotational speed ωs without driving the motor 21, the driving means 21 is driven. The control device 26 controls the drive unit 21 so that the amount of movement of the rotor 12 from the reference position is proportional to the square of the rotational speed of the rotor 12.

Next, the operation of the electric motor 10 configured as described above will be described.
When the electric motor 10 is driven, the coil 20 of the stator 18 is energized and a rotating magnetic field acts on the rotor 12. Then, the rotor 12 is rotated by the action of the rotating magnetic field and the magnetic flux of the permanent magnet 16. As the rotor 12 rotates, a centrifugal force acts on the protection member 17. Further, when the adhesive force of the adhesive bonding the permanent magnet 16 to the rotor core 15 becomes weak and the permanent magnet 16 is separated from the surface of the rotor core 15, the centrifugal force acting on the permanent magnet 16 also acts on the protective member 17. To do. And the protection member 17 will be in the state extended to radial direction by the effect | action of a centrifugal force.

  The relationship between the rotational speed of the rotor 12 and the extension amount of the protective member 17 at the rotational speed is determined. When the rotor core 15 has a constant outer diameter and the stator 18 has a constant inner diameter, the gap between the stator 18 and the protective member 17 is set based on the amount of extension of the protective member 17 at the maximum rotational speed of the rotor 12. When the rotor 12 is rotated at the maximum rotational speed, it is necessary to set so that the protective member 17 does not interfere with the stator 18. In that case, the set gap is too large during low-speed rotation, that is, a redundant air gap exists between the protective member 17 and the stator 18, and the motor characteristics such as torque reduction are deteriorated.

  The electric motor 10 is held at a reference position where the lower end of the rotor core 15 is at the same height as the lower end of the stator 18 as shown in FIG. 2A until the rotational speed of the rotor 12 exceeds a preset rotational speed. It is driven in the state. In this embodiment, the size of the gap between the protection member 17 and the stator 18 in a state where the rotor core 15 is disposed at the reference position is a value at which the protection member 17 does not interfere with the stator 18 due to the extension of the protection member 17 during high-speed rotation. Since it is set to a small value, a reduction in torque during low-speed rotation is prevented.

  When the rotational speed of the rotor 12 reaches a high speed exceeding a preset rotational speed, the driving means 21 is driven to move the rotor core 15 above the reference position, as shown in FIG. The rotor core 15 is formed in a truncated cone shape in which the outer diameter of the first end (upper end) is larger than the outer diameter of the second end, and the stator 18 has an inner diameter at the upper end that is larger than the inner diameter at the lower end. Since it is formed large, when the rotor core 15 is moved upward, the gap between the protection member 17 and the stator 18 becomes large. Even if the size of the gap in the state where the rotor core 15 is disposed at the reference position is set to a small value at which the protective member 17 interferes with the stator 18 due to the extension of the protective member 17 during high-speed rotation, the rotor 12 rotates at high speed. Sometimes the rotor 12 is moved. Therefore, even if the extension of the protection member 17 increases, the protection member 17 and the stator 18 do not interfere with each other.

  If the outer diameter of the rotor core 15 is constant, when the protective member 17 is formed uniformly, the elongation is the same at any position. However, the rotor core 15 is formed in the shape of a truncated cone, and the protective member 17 is formed by winding the reinforcing fiber so as to cover the permanent magnets 16 arranged on the outer periphery of the rotor core 15. Depending on the diameter.

The centrifugal force F acting on the rotating body is represented by the following equation.
F = mω ² r (1)
Here, m is mass, ω is angular velocity, and r is a turning radius.

  That is, the centrifugal force F is proportional to the square of the rotational speed (angular speed), and the extension amount of the protective member 17 is increased in a state proportional to the square of the rotational speed (angular speed). Therefore, the amount of expansion (expansion amount) in the radial direction of the protection member 17 is maximized at the upper end where the radius is maximum, and is minimized at the lower end where the radius is minimum. Fig.3 (a) shows the diameter of the upper end and lower end of the protection member 17, the state before a continuous line is extended, and the state after a dashed-two dotted line is extended.

  The control device 26 controls the drive means 21 so that the moving amount of the rotor 12 is proportional to the square of the rotational speed. As a result, the distance (gap) between the surface of the rotor core 15 and the inner surface of the stator 18 increases in proportion to the square of the rotational speed of the rotor 12, as shown in FIG. Therefore, even when the distance between the surface of the rotor core 15 and the inner surface of the stator 18 is made smaller than when the rotor 12 is moved at a constant speed, the protective member 17 does not interfere with the stator 18 and the gap is in an appropriate state. Change.

According to this embodiment, the following effects can be obtained.
(1) The rotor core 15 is formed such that the outer diameter of the first end is larger than the outer diameter of the second end, and the stator 18 has an inner diameter on the side corresponding to the first end of the rotor core 15. And larger than the inner diameter of the corresponding side. The permanent magnet 16 is fixed to the surface of the rotor core 15. That is, the permanent magnet 16 is disposed on the outer peripheral surface of the rotor core 15, and the outer peripheral portion of the first end portion is located radially outside the outer peripheral portion of the second end portion with respect to the rotor core 15. The gap between the protection member 17 and the stator 18 is changed by moving the rotor 12 relative to the stator 18 along the axial direction of the rotor 12. Therefore, without the redundant air gap between the protection member 17 and the stator 18 when the rotor 12 rotates at a low speed, interference between the protection member 17 for preventing scattering of the magnet and the stator 18 at the time of high speed rotation is prevented. can do.

  (2) The rotor 12 is relatively moved in the axial direction with the rotational speed of the rotor 12 exceeding a preset rotational speed, and the larger the rotational speed of the rotor 12, the more the outer peripheral surface of the rotor core 15 and the stator 18 It moves so that it may become the relationship between the rotational speed preset and the movement amount of the rotor 12 so that the distance with an internal peripheral surface may become large. Therefore, unlike the configuration in which the protection member 17 is gradually moved in the axial direction from the start of the rotation of the rotor 12, the rotor 12 does not move at a low rotational speed, and therefore the area of the rotor core 15 facing the stator 18 is reduced. A decrease in torque and a decrease in torque due to an increase in the distance between the outer peripheral surface of the rotor core 15 and the inner peripheral surface of the stator 18 can be suppressed.

  (3) The control device 26 controls the drive unit 21 so that the relative movement amount of the rotor 12 is proportional to the square of the rotational speed of the rotor 12. Therefore, compared with the case where the size of the gap provided so that the protective member 17 does not interfere with the stator 18 is set so that the movement amount of the rotor 12 is directly proportional to the rotational speed of the rotor 12, the rotational speed is low. The amount of movement can be reduced. Therefore, it is possible to suppress a decrease in torque accompanying a decrease in the area of the rotor core 15 facing the stator 18 as the rotor 12 moves.

  (4) The permanent magnet 16 is formed in a shape in which the line of intersection between the plane including the central axis of the rotor 12 and the outer peripheral surface is a straight line. Therefore, when the protection member 17 is configured by winding a fiber, the fiber can be easily wound as compared with a case where the intersecting line is inwardly convex.

  (5) The preset rotational speed at which the drive means 21 moves the rotor 12 in the axial direction is a rotational speed at which field weakening is required when the rotor 12 is not moved. The field weakening causes an extra d-axis current for reducing the magnetic flux to flow so that the induced voltage does not become excessive. Therefore, if the field weakening current is large, the efficiency of the electric motor 10 is reduced accordingly. In this embodiment, when the rotor 12 is not moved, if the field weakening exceeds the necessary rotational speed, the rotor 12 is moved and the gap between the protective member 17 and the stator 18 is increased. Accordingly, even if the field weakening current is reduced when the rotor 12 rotates at a high speed, the induced voltage can be prevented from becoming excessive, and it is not necessary to supply a large amount of extra d-axis current for reducing the magnet magnetic flux. Can be operated with high efficiency.

  (6) The drive means 21 moves the rotor 12 relative to the stator 18 by moving the rotor 12 in the axial direction. Therefore, it is easy to suppress the increase in size of the electric motor 10 as compared with the configuration in which the stator 18 is moved.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In this embodiment, the rotor core 15 and the drive means 21 are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4A, the outer shape of the rotor core 15 is formed in a truncated cone shape, and the length thereof is longer than the length of the stator 18. Specifically, the length of the rotor core 15 is equal to or less than the sum of the length of the stator 18 and the length of one side portion of the coil end 20a that is a portion protruding from both end surfaces of the stator 18 of the coil 20 wound around the teeth 19. (Same in this embodiment). In a state where the rotor core 15 is disposed at the reference position, the first end of the rotor core 15 has the same height as the first end of the stator 18 excluding the coil end 20a, and the second end of the coil end 20a. The stator 18 is arranged so as to protrude from the second end portion of the removed stator 18.

  Further, an angle θr formed by an intersection line between the plane including the central axis of the rotor core 15 and the outer peripheral surface forms an axial direction, and an angle θs formed by an intersection line between the plane including the central axis of the stator 18 and the inner peripheral surface forms the axial direction. It is not the same, and the angle θs is set larger than the angle θr. That is, when the rotor core 15 is disposed at the reference position, the distance between the upper end of the outer peripheral surface of the rotor core 15 and the upper end of the inner peripheral surface of the stator 18 is set to be the same as in the first embodiment. The distance between the lower end of the inner peripheral surface 18 and the outer peripheral surface of the rotor core 15 having the same height as the lower end is smaller than that in the first embodiment.

  The control device 26 controls driving of the driving unit 21 as in the first embodiment. In the configuration of the first embodiment, as the rotor core 15 is moved upward from the reference position, a part of the inner peripheral surface of the stator 18 does not correspond to the outer peripheral surface of the rotor core 15. However, in this embodiment, as shown in FIG. 4B, even when the rotor core 15 is moved to the uppermost position from the reference position, the inner peripheral surface of the stator 18 corresponds to the outer peripheral surface of the rotor core 15. That is, when the plane orthogonal to the rotation shaft 13 intersects with the inner peripheral surface of the stator 18, the rotor core 15 also intersects with the outer peripheral surface.

As described above, the centrifugal force F acting on the rotating body is represented by F = mω ² r. That is, the centrifugal force is proportional to the radius r. When the rotor 12 is rotating, the centrifugal force acting on the upper end portion of the protection member 17 is larger than the centrifugal force acting on the lower end portion of the protection member 17. Therefore, at the time of high-speed rotation of the rotor 12 at the reference position, the distance between the outer peripheral upper end portion of the rotor core 15 and the inner peripheral upper end portion of the stator 18 set so as to avoid interference between the protective member 17 and the stator 18, If the distance between the inner peripheral surface of the stator 18 and the outer peripheral surface of the rotor core 15 is set to be the same at any position, the distance of most parts is in a state where the safety factor is too high. However, in this embodiment, the distance between the inner peripheral surface of the stator 18 and the outer peripheral surface of the rotor core 15 is set so as to decrease toward the second end (lower end) side of the stator 18. Therefore, the distance can be made smaller than the safety factor that is too high, and the reduction in torque is suppressed.

Therefore, according to the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
(7) The axial length of the rotor core 15 is longer than the axial length of the stator 18. Then, in a state where the rotor core 15 is disposed at the reference position, the second end portion of the rotor core 15 is disposed so as to protrude from the second end portion of the stator 18, and the rotor core 15 is most moved from the reference position. Also, the inner peripheral surface of the stator 18 is formed to correspond to the outer peripheral surface of the rotor core 15. Therefore, in the state where the rotor core 15 has moved from the reference position, the torque obtained with the same amount of power usage increases.

  (8) The length of the end of the rotor core 15 protruding from the end of the stator 18 is set to be equal to or shorter than the length of the coil end 20 a protruding from the end face of the stator 18. Therefore, it can implement, without enlarging the physique of the housing 11. FIG.

  (9) In the state where the rotor core 15 is disposed at the reference position, the distance between the surface (outer peripheral surface) of the rotor core 15 and the inner surface of the stator 18 is such that the distance on the second end side is smaller than the distance on the first end side. Thus, the rotor 12 and the stator 18 are formed. Therefore, the distance can be made smaller than the safety factor that is too high, and the reduction in torque is suppressed.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In this embodiment, the shapes of the rotor core 15 and the stator 18 are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5A, the rotor core 15 is formed in a shape in which the intersection line between the plane including the central axis and the outer peripheral surface becomes a convex curve inward. The permanent magnet 16 provided on the surface of the rotor core 15 is formed in a shape in which a line of intersection between a plane including the central axis of the rotor 12 and the outer peripheral surface of the permanent magnet 16 becomes a convex curve inward. In addition, the stator 18 is formed in a shape in which a line of intersection between the plane including the central axis and the outer peripheral surface is a convex curve on the rotor core 15 side. For example, the curve that is an intersecting line with the outer peripheral surface of the rotor core 15 is set so that the outer diameter is a curve expressed by a cubic expression of the length in the axial direction.

The centrifugal force F acting on the protection member 17 is represented by F = mω ² r. That is, for the same mass and the same rotation speed, the centrifugal force is proportional to the radius r. And since the cylindrical protective member 17 is formed so that an outer diameter may become small gradually toward the 2nd end part side from the 1st edge part side, it receives a centrifugal force large toward the 1st edge part side. The mass m of the annular portion per unit length in the axial direction of the protective member 17 is represented by m = 2πrρ. However, ρ is specific gravity. Therefore, the mass m of the annular portion is also proportional to the radius, and the mass m of the annular portion increases toward the first end portion side. Further, since the circumferential length Lc of the annular portion in the unit length in the axial direction of the protection member 17 is expressed by 2πr, the circumferential length Lc of the annular portion is also proportional to the radius, and the circumferential length of the annular portion is closer to the first end side. The length Lc increases. If the Young's modulus is the same and the stress is the same, the amount of elongation of the annular portion increases in proportion to the circumferential length Lc. From the above, the radial extension amount generated in the protection member 17 as the rotor 12 rotates at high speed is proportional to the cube of the radius r.

  Therefore, when the rotor 12 rotates at a high speed, the rotor 12 is moved as shown in FIG. 5B in order to prevent the protection member 17 from interfering with the stator 18 as the protection member 17 extends. In this case, even if the movement amount is the same, the gap between the protection member 17 and the stator 18 on the second end side and the first end side of the rotor core 15 can be further reduced. As a result, it is possible to further suppress a reduction in torque accompanying an increase in the distance between the surface of the rotor core 15 and the inner surface of the stator 18.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The preset rotation speed for relatively moving the rotor 12 in the axial direction is not limited to the rotation speed at which the field weakening is required when the rotor 12 is not moved. For example, a speed lower than the rotational speed at which the field weakening is required when the rotor 12 is not moved may be set as a predetermined rotational speed. When the rotor 12 is rotated at a rotation speed larger than the rotation speed without moving the rotor 12 in the axial direction, the extension amount of the protection member 17 interferes with the stator 18. Since the rotation speed is set to a state, the appropriate rotation speed varies depending on the Young's modulus of the protection member 17 and the outer diameter of the protection member 17. Depending on the material and size of the protection member 17, the rotation speed of the rotor 12 is weaker than the rotation speed at which the field is required, and the extension amount of the protection member 17 interferes with the protection member 17 and the stator 18. Sometimes it becomes a state. Therefore, the setting of the rotational speed varies depending on the material and size of the protective member 17. Further, the rotation speed may be set to zero, and the movement of the rotor 12 may be started when the rotor 12 is rotated.

  The electric motor 10 is not limited to the one used in a state where the first end portion of the rotor core 15 is on the upper side and the rotating shaft 13 extends in the vertical direction. For example, it is configured such that the first end portion of the rotor core 15 is on the lower side, used in a state where the rotating shaft 13 extends in the horizontal direction, or used in a state where the rotating shaft 13 extends in an oblique direction. Also good.

  The drive means 21 that drives the rotor 12 to move relative to the stator 18 along the axial direction of the rotor 12 may be configured to move the stator 18 in the axial direction instead of the configuration that moves the rotor 12. Alternatively, both the rotor 12 and the stator 18 may be moved. However, the configuration in which the rotor 12 is driven is preferable in terms of suppressing an increase in the size of the rotating electrical machine.

  ○ The reinforcing fiber of the fiber reinforced resin constituting the protective member 17 is not limited to carbon fiber, but according to the required physical properties, inorganic fiber such as boron fiber, silicon carbide fiber, glass fiber, polyaramid fiber, poly-p- Organic fibers such as phenylene benzobisoxazole fibers and ultrahigh molecular weight polyethylene fibers may be used.

  ○ When the protective member 17 is formed by winding the fiber impregnated with an uncured thermosetting resin around the outer periphery of the magnet by filament winding and then heat-curing, both end portions of the rotor core 15 not provided with the protective member 17 are The pins are fixed to a jig protruding at a constant pitch in the circumferential direction. Then, the rotor core 15 may be attached to the filament winding device via the jig, and the fibers may be wound, and unnecessary portions may be cut and removed after heat curing. In this case, the fiber can be easily wound around the rotor core 15 whose outer diameter changes in the axial direction.

  The material of the protective member 17 is not limited to fiber reinforced resin, but is made of a nonmagnetic metal (for example, stainless steel), and a metal cylindrical body is fixed to the rotor core 15 not provided with the protective member 17 by beam welding. Or it may be fixed by shrink fitting.

  The control device 26 is not limited to the configuration provided in the electric motor 10, and is provided in the control unit of the inverter device that controls the electric motor 10, and the control unit of the inverter device has the function of the control device 26 that controls the driving means 21. It is good also as a structure.

  ○ The electric motor 10 is not limited to the combination of six permanent magnets 16 and the number of teeth 19, but may be an even number of permanent magnets 16. For example, the number of permanent magnets 16 is four (four poles). The number of teeth 19 may be 12, the number of teeth 19 may be six with four permanent magnets 16 (four poles), or the number of teeth 19 may be six with six permanent magnets 16. The number of teeth 19 is not limited to an even number and may be an odd number.

  When the control device 26 moves the rotor 12 relative to the stator 18 along the axial direction of the rotor 12, the outer peripheral surface of the permanent magnet and the inner peripheral surface of the stator are always accompanied by an increase in the rotational speed of the rotor. It is not limited to controlling the drive means so that the increase in the distance to For example, in a range where the rotational speed is low, there may be a range where the increase in the distance is constant as the rotational speed increases. Further, as in the second embodiment, when the second end portion of the rotor core 15 protrudes from the second end portion of the stator 18 at the reference position of the rotor core 15, a part of the protruding portion has a constant diameter. While using the rotor core 15 having a shape, the permanent magnet 16 may be shaped to match the surface shape. In this case, when moving the rotor 12 in the axial direction of the rotor 12, the distance between the inner peripheral surface of the stator 18 and the outer peripheral surface of the permanent magnet 16 at the second end portion of the stator 18 for a while after the movement starts. Becomes constant.

The permanent magnet 16 may be affixed to the surface of the rotor core 15 in contact with each other without providing a gap between the permanent magnets 16 adjacent to each other.
The stator 18 has only to be circular and the inside is almost circular, and the outer shape does not have to be circular. The outer shape may be a polygonal shape such as a quadrangle in accordance with the cross-sectional shape of the housing 11.

O You may apply not only to the electric motor 10 but to a generator.
The following technical idea (invention) can be understood from the embodiment.
(1) In the invention according to any one of claims 1 to 7, the axial length of the rotor core is formed longer than the axial length of the stator, and the rotor core is disposed at a reference position. In the state where the second end portion of the rotor core protrudes from the second end portion of the stator, the inner peripheral surface of the stator is also in a state where the rotor core is moved most from the reference position. It is formed so as to correspond to the outer peripheral surface of the rotor core.

  (2) In the invention according to any one of claims 1 to 7 and the technical idea (1), a surface of the rotor core and an inner surface of the stator in a state where the rotor core is disposed at a reference position. The rotor and the stator are formed such that the distance on the second end side is smaller than the distance on the first end side.

(A) is a block diagram of the electric motor in 1st Embodiment, (b) is a schematic diagram which shows the relationship between a stator and a rotor. (A) is a schematic cross section which shows the positional relationship with a stator in the state in which a rotor core exists in a reference position, (b) is a schematic cross section which shows the positional relationship when a rotor core moves. (A) is a schematic diagram which shows elongation of the small diameter side and large diameter side of a protection member, (b) is a graph which shows the relationship between the moving amount | distance of a stator, and rotational speed. (A), (b) is a schematic cross section corresponding to FIG. 2 (a), (b) in 2nd Embodiment. (A), (b) is a schematic cross section corresponding to Drawing 2 (a) and (b) in a 3rd embodiment. (A)-(d) is a model perspective view which shows the winding state of the single fiber around the magnet in a prior art. Sectional drawing of another prior art rotating field type AC generator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric motor, 12 ... Rotor, 15 ... Rotor core, 16 ... Permanent magnet, 17 ... Protection member, 18 ... Stator, 21 ... Drive means, 26 ... Control apparatus as control means.

Claims (7)

Magnet scattering prevention provided on the outer surface of the rotor core and the rotor core so that the outer peripheral portion of the first end portion covers a permanent magnet positioned radially outward with respect to the rotor core from the outer peripheral portion of the second end portion. A rotor having a protective member for,
A stator that is disposed outside the rotor and has an inner diameter on the first end side of the permanent magnet that is larger than an inner diameter on the second end side of the permanent magnet;
Drive means for driving at least one of the rotor and the stator so that the rotor moves relative to the stator along the axial direction of the rotor;
When the rotor and the stator are moved relative to each other by the driving means, the outer peripheral surface of the permanent magnet with respect to the increase in the number of rotations as the rotation speed of the rotor increases at least in a part of the number of rotations, A surface magnet type rotary electric machine comprising: control means for controlling the driving means so that an increase in distance from an inner peripheral surface is increased.   2. The surface magnet type rotating electrical machine according to claim 1, wherein the permanent magnet is formed in a shape in which a line of intersection between a plane including a central axis of the rotor and an outer peripheral surface of the permanent magnet is a straight line.   2. The surface magnet type rotating electric machine according to claim 1, wherein the permanent magnet is formed in a shape in which an intersecting line between a plane including a central axis of the rotor and an outer peripheral surface of the permanent magnet forms an inwardly convex curve.   When the rotor and the stator move relative to each other, the control means increases the distance between the outer peripheral surface of the permanent magnet and the inner peripheral surface of the stator as the rotational speed of the rotor increases. The surface magnet-type rotating electrical machine according to any one of claims 1 to 3, wherein the driving unit is controlled so as to increase a minute amount.   The said control means controls the said drive means so that the relative movement amount of the said rotor may be proportional to the square of the rotational speed of a rotor, when the said rotor and the said stator move relatively. The surface magnet type rotary electric machine according to any one of the above.   The surface magnet type rotating electrical machine is an electric motor, and the preset rotational speed at which the driving means relatively moves the rotor in the axial direction is a rotational speed at which field weakening is required when the rotor is not moved. The surface magnet type rotary electric machine according to any one of claims 1 to 5.   The surface magnet type rotary electric machine according to any one of claims 1 to 6, wherein the driving means moves the rotor relative to the stator by moving the rotor in an axial direction.

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